DE102018122837A1 - Electric turning tool with brake - Google Patents

Abstract

A turning tool or a machine (for example, an electric working machine) includes: an output shaft (22); a motor (30) that rotates the output shaft; a control part (16) for commanding the driving / stopping of the engine; and a control unit (40, 50) that controls the driving / stopping of the motor in accordance with commands from the operating part. The control unit is configured to generate a braking force for the engine or the output shaft when the engine is to be stopped, in proportion to a tightening force (torque) applied to the mounting tool when the engine is started such that the larger the Tightening force (torque) is, the greater the braking force.

Description

The present disclosure relates to an electric rotary tool or machine, for example, an electric machine having a rotatable output shaft on which tool accessories are mountable by tightening a screw, or by using another threaded connection such as bolts and nut.

TECHNICAL BACKGROUND

Known turning tools and machines, for example, grinding machines, circular saws, mowers and the like, have a tool attachment such as a grindstone, an incisor, a rotary cutting blade or the like mounted on a tip portion of a rotary output shaft using a threaded joint (for example Threaded fastener), such as nut and bolt or a screw is mounted.

A motor rotates the output shaft about an axis of rotation, thereby rotating the tool accessory. Consequently, the direction of rotation of the output shaft is fixed in the same direction, which also causes tightening of the screw or the nut with respect to the output shaft, while the engine accelerates the output shaft from standstill (zero rotations per minute) up to the operating speed. Thus, in such rotary tools and machines, when the engine is started and the output shaft is rotated from standstill to maximum speed (target speed) for operation, the screw or groove (lightly) rotates relative to the output shaft to relatively bias the tool accessory attracts to the rotary shaft, and thus the tool accessory remains securely fixed to the output shaft during operation.

In the rotary tool described in Japanese Patent Publication No. 2014-104536, disengagement of the tool accessory caused by rotating the fastening screw or lock nut in the releasing direction can be reduced or even prevented when an operation switch is turned off to prevent driving of the tool To stop the motor even if a braking force is generated by applying a braking current to the motor to stop the rotation of the motor (and thus the tool accessories) faster.

SUMMARY OF THE INVENTION

For example, the tightening force (torque) applied to the bolt or the nut holding the tool accessory on the output shaft when the engine is started increases in proportion to the engine speed increase, for example; For example, the larger the acceleration, the target torque, the angular momentum (acceleration integrated over time), etc. of the rotational output shaft, starting from the engine until the rotational output shaft has reached its target rotational speed, the greater the tightening force (torque) applied to the bolt , Nut, etc. (threaded fastener) is applied, and holds the tool accessory on the output rotary shaft during this time.

For example, if the user can variably set the target torque (the maximum torque) during operation (for example, by an external (manual) operation) when the engine is started, then the tightening force applied to the threaded attachment changes proportionally during engine starting to the specified target speed, assuming that there is always a constant acceleration applied to the rotary output shaft.

Accordingly, in Japanese Patent Laid-Open Publication No. 2014-104536 described above, when a braking current is applied to generate a braking force to stop the engine faster, it is necessary to set the braking force to a small value, so that the bolt becomes or does not loosen the screw holding the tool accessory on the output shaft when the tightening force (torque) applied to the jig or bolt during the engine start was small.

However, if a small braking force is always generated in the engine, then the larger the set (target) rotational speed is when the engine is driven to perform processing information, the longer the braking time that is required to stop the motor and the output shaft. As a result, the ease of use of the lathe tool or the machine under such circumstances (ie, at higher rotational speeds during operation) is adversely affected because the user must wait a long time for the tool accessory to stop rotating.

A non-limiting object of the present disclosure is to provide a technique for adjusting a braking force generated when the motor of a rotary tool is to be stopped so that the rotation of an output shaft can be stopped in a shorter time while simultaneously releasing the tool accessory that is mounted on the output shaft is minimized or prevented.

This object is solved by the subject matter of the independent claims. Further developments of the invention are specified in the dependent claims.

An electric turning tool or machine (eg, an electric working machine) according to a non-limiting aspect of the present disclosure includes: an output shaft configured so that a tool accessory can be mounted thereon by using a threaded connection (threaded connection) For example, a threaded fastener such as a screw or a bolt and a nut; a motor (electric motor) that rotates the output shaft directly or indirectly (for example, via a transmission such as a reduction gear, bevel gear, etc.); a control unit (for example, a switch, preferably a manual switch) for commanding (manual control) the driving / stopping of the engine; and a control unit that at least partially controls the driving / stopping of the motor based on commands from the operating part.

In addition, the control unit is configured to cause a braking force to be generated in the engine and / or applied to the output shaft when the engine is to be stopped. The control unit is configured to variably set the braking force in proportion to a tightening force (torque) acting on the tool accessory (more specifically, on the screw or nut holding the tool accessory on the output shaft) while the engine is being started (for example, from engine stall until the rotational output shaft has reached its target speed (maximum or peak speed) for the particular processing operation) such that the greater the attraction force (torque) during engine starting, the greater the braking force that can be applied when the engine is to be stopped.

According to the electric rotary tools or machines (for example, electric machines) according to this aspect of the present disclosure, when the tightening force (torque) applied to the threaded fastener holding the tool accessory on the rotary shaft during starting of the engine is small For example, when the motor is stopped, the braking force is preferably set to a relatively small value so that the loosening of the threaded fastener (eg, nut, screw, etc.) of the tool accessory during an engine stopping operation can be minimized or even prevented. As a result, the risk of the tool attachment falling unintentionally from the rotating shaft during operation can be reduced or possibly even eliminated.

On the other hand, when the speed increase, the acceleration, the angular momentum, etc. are large during starting of the engine, and hence the tightening force (torque) applied to the tool accessory is large (in other words, when the tool accessory fastener is safer). tightened) due to the faster engine starting), the time required to stop the engine can be shortened by applying (generating) a relatively large braking force to stop the engine faster compared to a case where a relatively small or no braking force is applied (generated).

Thus, according to this aspect of the present disclosure, by appropriately adjusting the braking force generated when (while) the engine is being stopped, the rotation of the output shaft can be stopped in a shorter time, while reducing or minimizing the likelihood that the fastener of the tool accessory is released during the deceleration (deceleration) of the output shaft.

According to an additional embodiment of this aspect of the present disclosure, the rotary electric tool or the engine may further include a speed setting part (eg, a dial, a switch, a slide switch, a toggle switch, up / down switch, etc.) that allows the user to set the target speed (Set maximum or peak speed) (for example, set manually) when the engine is driven during use of the turning tool or the machine. In such an embodiment, the control unit may be configured to control (variably set or set) the braking force applied while the engine is stopped, for example, in proportion to the target (maximum) rotational speed that has been set by using the rotational speed adjusting part. when the engine was started.

In this embodiment, the rotational speed setting part may be configured to set the target rotational speed (maximum rotational speed) when the motor is driven in proportion to the operation amount (manually adjustable movement) of the rotational speed setting part of the rotational speed setting part, for example, an amount of rotation (angular velocity change, an amount linear motion, etc. In such an embodiment, the control unit may be configured to control (variably adjust) the braking force when the engine is stopped, in proportion to the operation amount (positional adjustment, total movement, etc.) of the speed setting part.

In such embodiments, the control unit may be configured to control (increase / decrease) the braking force when the engine is stopped, in proportion to the (variable) tightening force (torque) applied to the tool accessory fastener while the engine speed of Zero to the target speed (maximum speed) that has been set manually using the speed setting part increases.

According to another embodiment, the control unit may be configured to determine the actual rotational speed (current rotational speed) of the engine (or the output shaft) when the command to stop the engine is input to the control unit (at the time when). In such an embodiment, when the rotational speed of the engine has not yet reached the target rotational speed (maximum rotational speed) set manually by using the rotational speed setting part when the command to stop the engine is input, the braking force can be set smaller be as a (greater) braking force that corresponds to the set target speed (maximum speed). Thus, the control unit may be configured to select or set the braking force in proportion to the actual speed (current speed) of the engine or the output shaft at the time when the command to stop the engine is given to the control unit, such as the braking force is lower for lower detected actual speeds (current speeds) and the braking force is greater for larger detected actual speeds (current speeds).

In other words, the control unit according to such an embodiment may be configured to select or set the braking force to stop the motor in proportion to the actual speed (current speed) at the time when the braking of the engine starts.

Thus, according to this aspect, the present disclosure can also be adjusted by appropriately setting (increasing / decreasing) the braking force that is generated while the engine is stopped, in proportion to the detected actual engine speed (current engine speed) (instead of the target engine speed (maximum engine speed) 1) adjusted by using the speed setting part), the rotation of the output shaft is stopped in a shorter time, while the likelihood that the tool accessory fastener comes off the output shaft during deceleration (deceleration) of the motor is still reduced or minimized becomes.

In another embodiment of the present disclosure, the control unit may be configured to directly control the braking force generated in the engine (or to which the rotational output shaft is applied) by controlling a braking current flowing to the engine while the engine is stopped is set (variable or fixed).

In addition, the control unit may optionally be configured to stop the engine when an engine stop command is input from the operating unit (eg, a manual ON / OFF switch) by first stopping the flow of current to the engine (without applying a braking current) A braking current is applied to the engine for a prescribed (predetermined stand-by time or waiting time, and then, after the prescribed (predetermined) waiting time has elapsed.) In such an embodiment, a lower braking force can be applied by appropriately setting the waiting time.

list of figures

• 1 FIG. 12 is an oblique view showing the overall structure of a grinding machine according to a first embodiment of the present disclosure. FIG.
• 2 shows a side view showing a portion of the grinding machine, where a tool accessory is mounted on a rotary output shaft of the grinding machine.
• 3 FIG. 12 is a block diagram showing the overall structure of a representative non-limiting drive system of the grinding machine. FIG.
• 4 FIG. 10 is a flowchart showing a representative, non-limiting control process executed by a controller. FIG.
• 5 FIG. 12 is an exemplary diagram showing a representative non-limiting plot (graph) different from that in FIG 4 The control process shown is used to set (select) a braking force.
• 6 shows time charts showing changes in the engine speed according to the first embodiment, wherein 6A is a timing chart for the case where a set speed is large (high), and 6B is a timing chart for the case where the set speed is small (low).
• 7 FIG. 12 is a flowchart showing a representative, non-limiting control process performed by a controller according to FIG A second embodiment is executed.
• 8th FIG. 11 is an exemplary diagram showing a representative non-limiting plot (graph) used to determine a waiting time in the in-game 7 specify (select) the control process shown.
• 9 shows time charts showing changes in the engine speed according to the second embodiment, wherein 9A a time chart is for the case where the set speed is large (high), and 9B a time chart in case the set speed is small (low).
• 10 FIG. 10 is time charts showing changes in engine speed according to a modified first example, wherein FIG 10A is a time chart for the case where the acceleration during startup is high, and 10B a time chart for the case where the acceleration during startup is low.
• 11 FIG. 10 is time charts showing changes in engine speed according to a modified second example, wherein FIG 11A is a timing chart for the case where the set speed is high during the startup and then the speed is manually reduced during operation, and 11B is a timing chart for the case where the set speed during startup is small and then the speed is manually increased during operation.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present disclosure will be explained below with reference to the drawings. It should be noted that in the embodiments described in detail below, a grinding machine is used for a workpiece that performs processing such as grinding, polishing, cutting or the like, and a non-limiting example of a rotary electric tool or A machine is (for example, an electric machine) according to the present disclosure, although the present teachings are generally applicable to any type of rotating tool or machine. In addition, it should be noted that the terms "rotary tool" and "lathe" can be used interchangeably and have the same meaning. Both terms are intended to describe devices that use power (eg, an electric current, a combustible fuel, etc.) to generate a rotational force that causes a tool accessory to rotate such that a workpiece is processed using the rotating tool can, or plant growth (such as grass, hedge, etc.) can be processed, and which have a fastener for the tool accessories or the tool accessory itself, which can unintentionally solve in a case in which an excessive braking force acts to the rotation the motor and / or the output shaft which rotates the tool to stop. Accordingly, no distinction should be made as to the use of only one "lathe tool" or "lathe" in the specification or claims, unless otherwise specified.

First embodiment

As in 1 shown have sander 2 or grinders according to embodiments which are described here, in principle, for example, a motor housing 4 , a gearbox 6 and a rear housing 8th on. The motor housing 4 has a circular cylindrical shape, which has an outer diameter (shell) that can be touched by a user, and takes a motor 30 (please refer 3 ) in its interior. The motor 30 located inside the motor housing 4 such that a rotary shaft of the motor 30 substantially parallel to the central longitudinal axis of the motor housing 4 is (or coincides with), and that the rotary shaft of the motor 30 to the transmission housing 6 protrudes.

The rear housing 8th located at one end of the central longitudinal axis of the motor housing 4 (More specifically on the side of the motor housing 4 that the transmission housing 6 opposite). In addition, there is a battery mounting area 8A at a rear end of the rear housing 8th provided on the side of the motor housing 4 opposite. A rechargeable battery pack 10 Thus, a DC power supply may be removably attached to the battery mounting area 8A to be assembled.

A slide switch (ON / OFF switch) 16 Allows the user to input commands (ON / OFF) manually to the motor 30 to drive / stop, and is located on the motor housing 4 , The slide switch 16 serves as a representative, non-limiting example of a keypad according to the present disclosure.

A speed change switch 18 The Dial Type allows the user to manually set the target speed (maximum speed) when the engine is running 30 is driven during a processing or machining operation, and is located on the rear housing 8th , Of the Rate changing switch 18 The dial type serves as a non-limiting representative example of a speed setting part according to the present disclosure. Such a switch 18 is also known as potentiometer, variable resistor, rheostat, etc.

It should be noted that although a rotatable speed change switch 18 is used by the dialing type in the present embodiment, so that the user (manually) the desired target speed of the engine 30 can variably set, for example, one or more buttons (for example, up / down) switch can be provided, instead of the speed change switch 18 of the dial type. In such an alternative embodiment, the speed of the engine 30 in steps proportional to the number of times the key switch (s) are pressed. For example, a first key switch may be provided to input a speed increase, and a second key switch may be provided to input a speed reduction. The two push buttons may optionally be incorporated in a single up / down switching unit. Such push buttons serve as another representative, non-limiting example of a speed adjustment part according to the present disclosure.

Of course, other types of speed adjustment parts / devices may be used in accordance with the present teachings. For example, a linear slide switch (linear potentiometer, resistance switch, etc.) may be used to provide speed signals to the control unit based on changes in resistance set by manually moving a lever or tab. A digital potentiometer can also be used. Moreover, the rotary electric tool or machine may be provided with a wireless communication device (eg, WiFi, Bluetooth®, near field communication, etc.) that allows the speed and / or other operating parameters to be used, for example, using an app or a smartphone, tablet , PCs, etc. can be set.

Referring to 2 is a spindle 22 , which serves as a representative, non-limiting example of an output shaft (rotational output shaft) according to the present teachings, rotatably mounted in the transmission housing 6 housed, and one end of the spindle 22 stands from the gearbox 6 in front. The spindle 22 is provided so as to have its central axis, which is the center of rotation, substantially orthogonal to the rotary shaft of the motor 30 is that of the motor housing 4 in the direction of the gearbox housing 6 protrudes. In addition, the spindle 22 with the rotary shaft of the motor 30 via a gear mechanism, located inside the gearbox 6 is located, coupled.

It should be noted that the gear mechanism is provided for converting the rotation of the motor 30 in a rotation of the spindle 22 and, for example, is formed by a bevel gear, etc .; Any other known rotary transmission configuration of known grinding machines or other electric rotary tools and machines, including, for example, reduction gears, may be used in accordance with the present teachings, and thus their detailed explanation is omitted.

An inner flange 24 is intended for positioning and fixing a tool accessory 12 which has a disc shape. The inner flange 24 is on the spindle 22 provided by the gearbox 6 protrudes. A locknut 26 holds the tool accessories 12 safe between the inner flange 24 and the locknut 26 by screwing it onto a thread on the spindle 22 is defined between the inner flange 24 and the tip of the spindle 22 , The locknut 26 serves as a representative, non-limiting example of a fastener of the tool accessory according to the present teachings. The locknut 26 and the threaded spindle 22 can be replaced by, for example, a screw which is screwed into a threaded hole defined in the spindle (output shaft). Of course, in accordance with some alternative embodiments of the present disclosure, the tool accessory itself may include a fastener (eg, an integrally formed fastener) connecting the tool accessory to the output shaft, such as via a threaded connection or threaded fastener (threaded fastener).

By providing (providing) the tool accessories 12 between the inner flange 24 and the locknut 26 , and then by tightening the locknut 26 in the direction of the inner flange 24 , therefore, can the tool accessories 12 safely on the spindle 22 be attached. It should be noted that in the grinding machine 2 According to the present embodiment, a grindstone, cutting stone, wire brush, etc. serve as representative, non-limiting examples of a tool according to the present disclosure. For example, in other embodiments of the present teachings, rotating cutting blades, wheels, grinding wheels, etc. may be used as rotatable tool accessories, depending on the particular application of the present teachings.

In addition, a wheel cover 14 be provided to the user before scattering of material parts of the workpiece, from the tool accessories 12 or the like during the machining operation, such as grinding, polishing or cutting. The wheel cover 14 is safe on the gearbox 6 around the projecting area of the spindle 22 attached around.

It should be noted that the wheel cover 14 has substantially a semicircular shape such that these from the side of the transmission housing 6 from an area (substantially half in the present embodiment) of the tool 12 attached to the spindle 22 is attached, covering.

Referring to 3 get an inverter 40 and a controller 50 electrical power from a battery 20 inside the battery pack 10 and serve as a representative, non-limiting example of a control unit for driving / stopping the engine 30 according to the present disclosure. The inverter 40 and the controller 50 are in the rear housing 8th accommodated.

The motor 30 is preferably a three-phase brushless motor, and the inverter 40 may comprise a known bridge circuit capable of the current path to each phase winding of the motor 30 to switch. The inverter 40 preferably comprises three switching devices connected between a positive electrode of the battery 20 and terminals of the phases U, V, W of the motor 30 are provided, and three switching devices connected between a negative electrode of the battery 20 and terminals of the phases U, V, W of the motor 30 are provided.

In such an embodiment, when the engine 30 is to be stopped, a desired braking force can be generated, for example by: Short-circuit brakes of all phases, in which a braking current to all windings of the engine 30 over the inverter 40 is created; or a two-phase short-circuit braking in which a braking current is applied to some (for example, two) of the windings of the motor 30 is created.

It should be noted that various types of brake control in which the braking force is adjusted (varied) by switching the short-circuit braking in this manner, for example, described in detail in the Japanese Patent Laid-Open Publication No. 2013-243824 and the corresponding US 2013/307446 the disclosure of which is hereby incorporated by reference. Consequently, a detailed explanation of the brake control techniques will be omitted.

In addition, there is a resistance 42 for detecting an electric current in the current path extending from the inverter 40 to the negative electrode of the battery 20 extends, and the voltages on both sides are in the controller 50 via a current detection part 44 entered.

In addition, a rotation detection part detects 32 the rotational position of the engine 30 (in other words, the rotation angle: electrical angle) and is on the engine 30 intended. The rotation detection part 32 preferably has Hall sensors located around the rotor of the motor 30 around at 120 ° intervals of the electrical angle, and the output from each Hall sensor is undulating and then enters the controller 50 entered.

In the control 50 thus becomes the rotational position of the motor 30 detected by the edge of the input signal from each Hall sensor at 60 ° electrical angle intervals, and the speed of the motor 30 can be calculated from the edge intervals. It should be noted that in the present description, the rotational speed of the engine 30 is equal to the number of revolutions of the motor rotor per unit time (for example, rotations per minute or "rpm").

The control 50 preferably comprises a microcomputer (for example, a microcontroller) having a CPU and a memory, such as a ROM and RAM, and driving / stopping the motor 30 becomes in accordance with the ON-OFF state of the slide switch 16 switched, which is operated by the user (manually operated). As explained later, one or more programs (set or sets of instructions) are stored in the memory which, when executed by the CPU, control 50 and the inverter 40 to perform various functions described above and below.

If the engine 30 In addition, the controller reads 50 from the speed change switch 18 of the dial type, the target speed (maximum speed) set by the user and controls the energizing current supplied to the motor 30 is delivered by the inverter 40 used so that the actual speed of the engine 30 becomes equal to the set target speed. The target speed set by the user is thus the desired maximum speed of the spindle 22 (and therefore the tool accessories 12 ) during a workpiece machining operation.

In addition, if the engine 30 is to be stopped, the controller performs 50 a brake control by applying one or more selected (described below) braking currents to the engine 30 be created by the inverter 40 is used by switching the short-circuit brake described above, whereby the desired (suitable) braking force is generated.

A representative, non-limiting example of a control process (algorithm) used by the controller 50 is executed in this manner will be described below with reference to the in 4 explained flowchart explained. As in 4 is shown in S110 of the control process executed by the controller 50 is executed, the control process (control unit) first ready for the switch SW 16 to be switched to the ON state by determining whether the slide switch 16 (hereinafter referred to as slider SW) in the ON state. For example, the controller 50 detect when a current through the slide switch 16 flows to determine that the slide switch SW 16 is in the ON state.

When it has been determined that the switch SW 16 has been switched to the ON state, then the control process jumps to step S120 where the target speed of the engine 30 set by the user (manually) from the speed change switch 18 is read from the dial type, and then the control process jumps to step S130 ,

In S130 the engine drive process is performed, in which the engine 30 is driven so that the speed of the motor 30 based on the detection signal from the rotation detection part 32 is calculated equal to the set speed. Then the process is in step S140 continued, where the control process determines whether the switch SW 16 has been switched to the OFF state. For example, the controller 50 Check for a current through the switch 16 flows to determine that it is in the OFF state. The control process jumps to step again S120 when the switch SW 16 has not been switched to the OFF state, or skips to step S150 when the switch SW 16 has been switched to the OFF state.

In S150 is determined by the motor drive process of S130, whether the speed of the motor 30 has reached the target speed (up to this has risen), using the speed change switch 18 has been set by the dialing type. If in S150 it is determined that the speed of the motor 30 has reached the set speed, then the control process jumps to step S160 and sets the braking force or selects the braking force to be generated by the brake controller based on the set speed. The control process then jumps to step S180 to execute the brake control.

In contrast, if it is determined in S150 that the speed of the motor 30 has not yet reached the set speed, then the control process changes to step S170 and sets (selects) the braking force to be generated by the brake controller based on the actual rotational speed (current rotational speed of the engine 30 ). The control process then changes to step S180 to perform the brake control.

It should be noted that a predetermined (stored) schedule (graph, look-up table, etc.) can be used to determine the braking force in the steps S160 or S170 set so that the higher the speed of the engine 30 is when the slide switch 16 is turned off, the greater the braking force acting during the brake control, as in 5 shown.

In S180 a brake controller suitable for generating the braking force set in S160 or S170 is selected from a plurality of brake control types each having a different braking current; wherein, by performing the selected brake control, a braking force in the engine 30 is produced.

It should be noted that in S180, the short-circuit braking suitable for generating the set braking force may be selected from a plurality of predetermined short-circuit brake types. The majority of the types of particular short-circuit braking include short-circuit braking of all phases and two-phase short-circuit braking as mentioned above. The two-phase short-circuit braking is further categorized into different types depending on the number of switching devices used or the like.

While the brake control is performed in S180, the control process in S190 determines whether the engine 30 is stopped (in other words, whether the speed has become zero). If the controller 50 determines that the signal from the rotation detection part 32 For example, control may not change or has changed by less than a threshold 50 determine that the engine 30 is stopped. If it has been determined in S190 that the engine 30 is not stopped, then the control process jumps again to step S180 and continues the braking control; on the other hand, if it has been determined in S190 that the engine 30 is stopped, the control process ends for the time being.

As explained above, the grinder is 2 according to the present embodiment, configured such that the rotational speed when the engine 30 is driven during a machining operation, can be variably set using the speed change switch 18 of the dial type. In such an embodiment, when the slide switch 16 is switched to the ON state by the user, the controller determines 50 that a command to drive the engine 30 has been entered, starts the engine 30 and performs the drive control for the motor 30 such that the speed of the engine 30 equal to the set speed is (or rises to this).

When the slide switch 16 in the OFF state is switched by the user while the engine 30 is driven, then determines the controller 50 that a command to stop the engine 30 has been entered, and thus the controller stops driving the motor 30 (ie the delivery of an energization current to the motor stops) and starts the brake control.

In the brake control according to the present embodiment, moreover, in the engine 30 generated braking force is controlled in proportion to the set target speed, which is the target speed when the engine 30 is started, so that the larger the set speed, the greater the braking force applied during brake control.

As in 6A shown when the set target speed at start (time t0) of the engine 30 is high and the engine 30 is driven to the set target speed, is corresponding to the engine 30 delayed by a relatively large braking force is applied when the slide switch 16 is switched off (time t1).

This relatively large braking force is permissible because, if the set target speed is relatively high, the tool accessories 12 safely on the spindle 22 through the lock nut 26 fastened (tightened) due to the increase in speed (acceleration) after starting the engine 30 , In this case, although a large braking force is generated by the brake control when the engine 30 is stopped so can the engine 30 be stopped in a short time without the lock nut 26 that are the tool accessories 12 at the spindle 22 attached, detached.

In contrast, as in 6B shown when the target speed when starting (time t0) of the engine 30 has been set, is small (relatively small) and the engine 30 only driven to this low set target speed, the engine is 30 delayed by applying a relatively small braking force when the slide switch 16 is switched off (time t1).

This lower braking force is required because, if the set target speed is relatively low, the speed of the motor 30 achieved after starting the set target speed in a relatively short time; hence, during the engine startup phase, as compared with the case where the set target revolution speed is high, the lock nut becomes 26 and consequently the tool accessories 12 less firmly tightened or fastened. In this case, therefore, the braking force generated by the brake control is set to a relatively small value, and hence the engine becomes 30 Delayed slower to the likelihood of the lock nut 26 triggers, due to the brake control, which is performed when the engine 30 is stopped, minimized or even eliminated.

According to the grinder 2 Accordingly, in the present embodiment, by controlling (correspondingly increasing / decreasing) the braking force generated by the brake control while the engine is running 30 is stopped, the rotation of the engine 30 be stopped in a shorter time, while minimizing the risk or preventing the lock nut 26 dissolves during brake control.

In the present embodiment, when the slide switch 16 is switched off (time t2), within the interval starting from the engine start until the engine speed 30 reaches the set target speed (ie the slide switch 16 is turned off at a time when the rotational speed is less than the set target rotational speed) as indicated by the broken line in FIG 6A is shown, then the braking force, which is generated by the brake control, based on the actual (current) speed of the engine 30 set at this time.

In this case, in which the brake control is performed from time t2 on, the engine becomes 30 with a braking force smaller than a (larger) braking force corresponding to the set target speed, and thus it is possible to minimize the risk or prevent excessive braking force from acting as compared with the lock nut tightening during the engine start. According to the grinder 2 of the present embodiment, therefore, the risk that the lock nut 26 as a result of the braking force triggers, further minimized or even prevented.

Second embodiment

In the first embodiment, it has been described that when the slide switch 16 is turned off and consequently a command to stop the engine 30 is entered, then the brake control is performed, and in this brake control, the braking force in the engine 30 due to the braking current leading to the motor 30 flows, is generated, is controlled (is variably adjusted, as required with respect to the speed of the motor 30 ).

In contrast, in the second embodiment, when a command for stopping the engine 30 is input, the flow of the flow to the engine 30 first interrupted for a prescribed (predetermined) waiting time, without applying a braking force, and after lapse of the waiting time, the brake control is then performed by the braking current to the motor 30 is supplied, similar to the first embodiment.

The braking force after the input of the stop command may be preferably reduced or minimized by the waiting time interval from the time when the flow of the current to the motor 30 is interrupted until the start of the brake control (ie a braking current to the motor 30 supplied) can be set (increased / reduced).

A representative, non-limiting control process (algorithm) used by the controller 50 is executed to perform the brake control in this manner will be described below with reference to the in 7 explained flowchart explained.

Because the control process, as in 7 shown having some same steps as the control process according to the first embodiment, which in 4 11, only those items (steps) other than the control process according to the first embodiment will be explained below. A description regarding the remaining steps will hereby be made with reference to the above description of the control process according to FIG 4 added.

As in 7 when it is determined in S140 that the switch SW 16 has been switched to the OFF state, and thus a command to stop the engine 30 has been entered, the control process jumps to S145 and driving the engine 30 is stopped by all switching devices in the inverter 40 be switched off (so there is no Energetisierungsstrom to the engine 30 provided). It should be noted that when driving the engine 30 stopped in this way, the engine 30 in a freewheeling state and consequently delayed relatively slow because no braking force (braking current) to the engine 30 created or generated in this. Only internal frictional forces of bearings, gears, etc. cause a slow deceleration of the engine 30 and the spindle 22 ,

When driving the engine 30 in S145 is stopped, the control process jumps to S150 , and it is then determined whether the speed of the engine 30 has reached the set target speed. When in S150 it is determined that the speed of the engine 30 has reached the set target speed, the control process jumps to step S165 , and the waiting time for waiting until the brake control is started is set (selected) based on the set target speed.

If in contrast S150 it is determined that the actual (current) speed of the motor 30 has not reached the set target speed, then the control process jumps to step S155 and the waiting time for waiting until the brake control starts is set (selected) based on the actual (current) rotational speed of the engine 30 instead of based on the set target speed, which is higher than the actual (current) speed.

It is noted that a predetermined (stored) schedule (graph, look-up table, etc.) can be used to estimate the waiting time in the steps S165 or S155 adjust, such that the higher the speed of the motor 30 at the time of turning off the switch 16 is, the shorter the waiting time, as in 8th shown.

After the wait in S165 or S155 has been set, the control process jumps to S175 and then wait until the set waiting time has elapsed. When in S175 is determined that the waiting time has elapsed, then the control process jumps to step S180 and causes a prescribed braking force in the engine 30 is to be generated by performing the brake control using the above-described predetermined (stored) short-circuit braking.

It should be noted that when (while) the brake control is in S180 is performed, the control process in S190 determines if the engine 30 is stopped; if the engine 30 is not stopped, then will S180 further elaborated; on the other hand, if the engine 30 is stopped, then the control process ends for the time being.

In the grinding machine 2 according to the present (second) embodiment, when a command for stopping the engine 30 is entered, is therefore driving the engine 30 (the supply of Energetisierungsstroms) stopped for a prescribed waiting time, without a braking force in the engine 30 is generated, and then after lapse of the waiting time, the brake control is started. In addition, the waiting time can be set in proportion to the set speed, which is the target speed when the engine 30 is started, such that the larger the set target speed, the shorter the waiting time.

As in 9A shown when the set speed at start (time t0 ) of the motor 30 big, and the engine 30 is driven to this set speed, and then the slide switch 16 is switched off (time t1 ), the brake control is started immediately with little or no waiting time.

This short waiting time is allowed because when the target speed set during the motor startup is high, the tool accessory 12 through the lock nut 26 safely on the spindle 22 due to the speed increase (acceleration) after starting the engine 30 , In this case, even if the brake control is started (that is, the braking force applied / generated) immediately when driving the engine 30 is stopped, so can the engine 30 be stopped in a shorter time, without the risk of having the lock nut 26 (and consequently the tool accessories 12 ) releases.

In contrast, as in 9B shown when the target torque at startup (time t0 ) of the motor 30 has been adjusted, is low, and the engine 30 is driven to this low set target speed, when the slide switch 16 is switched off (time t1 ), driving the engine 30 stopped and a longer waiting time is set according to the lower target speed. Since the brake control is not performed in the waiting time state (standby state), the engine rotates 30 due to inertia until the waiting time has elapsed and the speed of the motor 30 decreases slowly, increasing the risk of the lock nut 26 solves, is avoided.

When the wait after driving the motor 30 stopped (time t1 ), has elapsed (time t3 ), so the brake control is started and the braking force in the engine 30 generated. Then the engine delays 30 faster, due to the generation / application of this braking force and is finally stopped.

According to the grinder 2 According to the present (second) embodiment, by reducing the waiting time to wait until the brake control is started after driving the engine 30 has been stopped (in a case where the speed of the engine 30 is high), the braking time that is required to the engine 30 be stopped by the drive state.

In such a brake control, when the engine 30 thus rotating at high speed, a large braking force can be used to stop the engine 30 be created, and if the engine 30 Turns at low speed, a lower braking force to stop the engine 30 created.

At the grinding machine 2 According to the present (second) embodiment, also the rotation of the motor 30 be stopped in a shorter time, while the risk can be minimized or prevented that the lock nut 26 during the deceleration of the engine 30 solves.

Modified Example 1

In the above embodiments, it has been described that, after a command for stopping the engine 30 into the controller 50 has been entered, the braking force generated when the engine 30 is stopped, including (optional) the waiting time, is set based on the set speed when the engine 30 is started.

In the above embodiments, the acceleration of the engine 30 during starting (ie from standstill to reaching the target speed) either constant (or substantially constant) or follows a predetermined acceleration profile (pattern), so that the attractive force (torque) applied to the lock nut 26 is applied during starting of the engine, directly (directly proportional) corresponds to the target speed, or a lower speed in the case where the target speed has not been reached when the slide switch 16 has been turned off. As the extent of the tightening force (torque), which is on the lock nut 26 acts, the acceleration rate (more specifically the acceleration of the output shaft integrated over time, which is also known as "angular momentum") corresponds to the peak speed directly corresponds to the angular momentum. In such embodiments, therefore, the braking force (braking current) and optionally the waiting time can be selected from predetermined (prescribed) braking forces (braking currents) and waiting times stored in the rotary electric tool and corresponding to the peak speed.

When an acceleration adjustment part 52 (by the dashed line in 3 shown) is provided for manual adjustment (Select) the extent of acceleration when the engine 30 is started, then the braking force (variable) can be set, at least partially based on the acceleration, by the user using the acceleration setting part 52 has been adjusted.

As in 10A shown when the acceleration is high (high), while the speed increases up to the set target torque after starting (time t0 ) of the motor 30 , then the braking force is in the engine 30 is generated due to the brake control after driving the motor 30 has been stopped (time t1 ) also preferably relatively high (large).

If, on the other hand, as in 10B shown, the acceleration is low, while the speed increases up to the set target speed after starting (time t0 ) of the motor 30 , is the braking force in the engine 30 is generated due to the brake control after driving the motor 30 has been stopped (time t1 ) also preferably relatively low.

By reducing the braking force generated by the brake control while the engine is running 30 is stopped, if a lower acceleration is set during the engine start, consequently, the rotation of the motor 30 can still be stopped in a shorter time without increasing the risk that the lock nut 26 during brake control triggers.

It should be noted that although the set speed when the engine 30 is started, a fixed target speed in 10 Embodiments may be configured such that both the target speed (peak or maximum speed) and the acceleration when the motor 30 is started, can be set (manually) by the user. In addition, in such an embodiment, the braking force applied during the engine 30 is stopped by the brake control is generated (or the waiting time according to the second embodiment) are set using the set target speed and the set acceleration.

In such embodiments, moreover, the user may manually (variably) set both the acceleration and the target speed (peak or maximum speed) for a particular machining operation, however, it is possible for the slide switch 16 is turned off before the engine 30 reaches the target torque. Also in this case, the braking force (and optionally the waiting time) may optionally be based on the set acceleration and the peak speed provided by the engine 30 is reached before the power to the motor 30 is interrupted, be set. For example, according to an embodiment, predetermined maps, graphs, look up tables, etc. may be stored in the control unit, and the braking force (and optionally the waiting time) may be selected by entering the set (target) acceleration and peak speed before the engine 30 is turned off. According to another embodiment, the control unit may store a program that calculates the angular momentum applied to the output shaft, for example, by integrating the set acceleration over time during which the motor 30 is accelerated. The braking force may then be selected based on the calculated angular momentum, so the braking force may be selected in proportion to the calculated angular momentum.

Modified Example 2

In the above embodiments, although it has been described that the target rotational speed when the engine 30 is started, is set via the speed change switch 18 of the dial type, the above embodiments may be configured (modified) such that the target speed is not limited to be set only when the motor 30 is started. Instead, the target speed may be modified (increased / decreased) by the user at any time during the machining process.

The above embodiments may be configured (modified) so that the user can modify (increase / decrease) the set target speed at any time by using the speed change switch 18 is used by the dial type, or by a trigger manipulation part 54 is used in 3 is shown. It should be noted that the trigger manipulation part 54 is generally known and has a trigger (trigger switch) for the user to operate (manipulate) by pulling and is configured such that a speed command to the motor 30 proportional to the extent to which the trigger is actuated (pulled).

If the grinder 2 configured in this manner, then, even if the set speed, when the engine 30 is started, is greater than in 11A shown, and / or even if the set speed when the engine 30 is started smaller than in like 11B shown, the set target speed while driving the engine 30 manually modified.

Even if the initial value of the set target speed is changed, the control is 50 configured to be set based on the set speed (the initial value) when the engine 30 is started, the braking force generated by the brake control (or the waiting time) when the engine 30 is stopped, in the same manner as in the embodiments described above.

It can be when stopping the engine 30 generated braking force equal to the tightening force, with the lock nut 26 (and consequently the tool accessories 12 ) is tightened (fastened) due to the speed increase (acceleration, angular momentum, etc.) of the motor 30 when the engine 30 is started, and therefore it is possible to reduce the risk or suppress the counter nut 26 (and consequently the tool accessories 12 ) when the brake control is performed.

Although embodiments of the present disclosure have been explained above, the present disclosure is not limited to these embodiments, and it should be understood that changes and modifications can be made without departing from the scope of the invention.

Although it has been explained in the above embodiments that the set speed when the engine 30 is started, is used to adjust the braking force generated by the brake control (or the waiting time) when the engine 30 For example, the amount of manipulation (manual adjustment) of the speed setting part may be used instead. Specifically, the braking force generated by the brake control (or the waiting time) may be adjusted by adjusting a variable speed position of the speed changeover switch 18 of the dial type, the operation amount of the trigger manipulation part 54 or the like can be used.

In the above embodiments, moreover, grinding machines have been made 2 described in which the engine 30 is configured as a three-phase brushless motor and is operated by receiving an electric power from the battery 20 , However, the technology of the present disclosure can be adapted at all times to other embodiments in the same manner as in the above embodiments even if, for example, a rotary electric tool or a machine (for example, an electric working machine) is used, where the motor is a DC motor with brushes, and is powered by receiving an electrical power (current) from an AC power supply.

In the above embodiments, it has been described that when the engine 30 is stopped, the braking force is generated by the braking current to the motor 30 is delivered. However, an electric turning tool or a machine (for example, an electric working machine) may be configured such that, for example, a mechanical brake device (a disc brake, a pad, or the like) on the rotating shaft of the motor 30 or on the spindle 22 is provided, and the rotation is directly (mechanically) braked (for example, by friction) by the braking device. Even in such embodiments, by adjusting the braking force using the brake device according to the present teachings, the same effects as in the above embodiments can be obtained.

Although in the above embodiments grinding machines 2 have been described as a representative example of the electric rotary tool or the machine (eg, electric machine), the present teachings are applicable to any device configured such that the tool accessory (or a threaded fastener) by the speed increase, acceleration , Angle pulse, etc., is fixed on the output shaft when the engine is started, and a braking force is generated by a brake control to stop the engine faster. Specifically, for example, circular saws, mowers, etc. may be given as additional representative examples of the rotating tools and machines to which the techniques of the present disclosure may be applied.

Moreover, a plurality of functions having a structural member in the above embodiments may be implemented by a plurality of structural members, a function having a structural member may be implemented by a plurality of structural members, and so on. Moreover, a plurality of functions having a plurality of structural members may be implemented by a structural member, a function implemented by a plurality of structural members may be implemented by a structural member, and the like. In addition, some of the structural components may be omitted in the above embodiments. In addition, at least one of the structural members in the above embodiments may be added or replaced by structural members in other above-mentioned embodiments. It should be noted that any aspect contained in the technical concepts resides in the claims is an embodiment of the present invention.

Representative, non-limiting examples of the present invention have been described above in detail with reference to the accompanying drawings. This detailed description is merely to assist one of ordinary skill in the art with further details for practicing the aspects of the present teachings and is not intended to limit the scope of the invention. Moreover, each of the additional features and teachings disclosed above may be used separately or in combination with other features and teachings to provide improved turning tools and machines.

Moreover, combinations of features and steps disclosed in the above description are not necessarily required for practicing the invention in its broadest sense, and instead merely serve to describe specific representative examples of the invention. In addition, various features of the above-described representative examples, as well as various independent and dependent claims described below, may be combined in ways that have not been specifically and explicitly stated to provide further useful embodiments of the present teachings.

All features disclosed in the specification and / or claims are intended to be separately and independently disclosed for the purpose of original written disclosure, as well as for the purpose of limiting the claimed subject matter, regardless of the composition of features in the embodiments and / or the claims. In addition, all ranges of values and indications of groups of units are intended to encompass every possible intermediate value or entity for the purpose of the original written disclosure, as well as for the purpose of limiting the claimed subject matter.

Although some aspects of the present disclosure have been described in the context of a device, it should be understood that these aspects also represent a description of a corresponding method such that each block or component of a device, such as the control unit (controller 50 and the inverter 40 ) can also be understood as a corresponding method step or as a feature of a method step. Similarly, aspects described in the context of a method step or as a feature of a method step also represent a description of a corresponding block or detail or feature of a corresponding device, such as the controller.

Depending on certain implementation requirements, example embodiments of the control unit according to the present disclosure may be implemented in hardware and / or software. The implementation may be configured using a digital storage medium, for example, by using one or more of ROM, PROM, EPROM, EEPROM, or flash memory on which are stored electrically readable control signals (program code) that can interact or interact with a programmable hardware component so that the respective procedure is carried out.

A programmable hardware component may be formed by a processor, a computer processor (CPU), an application specific integrated circuit (ASIC), an integrated circuit (IC), a computer, a system on chip (SOC), a programmable logic device or a programmable field array (FGPA) including microprocessor.

The digital storage medium may thus be machine-readable or computer-readable. Thus, some exemplary embodiments include a data carrier or a non-transitory computer-readable medium having electronically-readable control signals that may interact with a programmable computer system or a programmable hardware component such that one of the methods described herein may be performed. An exemplary embodiment is thus a data carrier (or a digital storage medium or a non-transitory computer-readable medium) on which the program is stored for performing one of the methods described herein.

In general, exemplary embodiments of the present disclosure, in particular the control unit, are implemented as a program, firmware, computer program or computer program product having a program, or as data, wherein the program code or data is operative to perform one of the methods, if Program is executed on a processor or a programmable hardware component. The program code or the data can also be stored on a machine-readable carrier or a data carrier, for example. The program code or the data may include source code, Machine code, bytecode or other intermediate code.

A program according to an example embodiment may implement one of the methods during its execution, for example, such that the program reads memory locations or writes one or more data elements into those memory locations, wherein switching operations or other operations in transistor structures, amplifier structures, or other electrical, optical, magnetic components or components based on other functional principles. Accordingly, data, values, sensor values or other program information can be detected, determined or measured by reading out a memory location. Thus, by reading from one or more memory locations, a program may acquire, determine, or measure quantities, values, variables, and other information, as well as initiate, induce, or write an action by writing to one or more memory locations, as well as other apparatus, Control machines and components.

Although some aspects of the control unit have been identified as "parts" or "steps," it should be understood that such parts or steps need not be physically separate or different in electrical components, but instead may represent different blocks of program code executed by the same hardware component be, for example, by one or more microprocessors.

Other embodiments of the present disclosure include the following modifications, which are not limitative.

For example, in the second embodiment described above, the controller determines 50 the speed of the output shaft of the motor M when the switch 16 is turned off, and then sets a waiting time to wait until the brake current is applied. However, instead of setting a wait time, it is also possible to monitor the speed of the output shaft and wait until the speed is below a threshold before applying the brake current.

The control 50 For example, it may be configured to monitor the rotational speed of the output shaft based on signals from the rotational speed detection part 32 , in the freewheeling state (ie when the inverter 40 no longer the engine 30 drives so that the output shaft rotates only due to inertia). If the controller 50 determines that the speed falls below a preset threshold (predetermined speed), then the braking current is applied to stop the output shaft faster, similar to the second embodiment described above.

In addition, in each of the embodiments described above and below, the braking force (or braking current) applied to the motor M may either have a fixed (constant) value, or may be variable.

Paragraphs [0031] - [0033] and [0138] of US 2013/307446 for example, disclose exemplary embodiments with variable braking force and teachings of these paragraphs are hereby incorporated by reference.

According to an embodiment of the present teaching with a variable braking force when the motor M rotates too fast such that full braking (maximum braking) is not performed without the risk of the lock nut 26 solves, therefore, a smaller braking force can be applied initially, while the engine rotates relatively quickly. Thus, although the full braking force is not applied, the motor M can still be actively decelerated, shortening the time until the output shaft stops, but by an amount of deceleration (braking force) that does not release the lock nut 26 caused.

As the rotational speed of the engine M is further decelerated, the braking force can be increased, either continuously or stepwise in discrete steps.

In such embodiments with variable braking, the total braking time can be shortened without increasing the risk of the lock nut 26 solves, compared to the case in which the engine can rotate in the freewheeling state (for example, during a waiting time) until the maximum braking force (full braking force) can be applied.

In addition, all of the embodiments described above use short-circuit braking by applying a braking current to the motor M or by using a mechanical brake (eg, brake pads or brake discs). However, in addition to or instead of applying a braking current to the motor M and / or using a mechanical brake, a dynamic resistance brake may be used to generate a braking force in the motor M, for example by using resistive brake embodiments incorporated in US Pat US 9,776,338 are disclosed, the contents of which are incorporated herein by reference.

In such embodiments with a dynamic resistance braking can a Resistor be connected to the motor M to a braking force in the engine 30 to generate when the rotation of the output shaft to be braked. In such embodiments, the controller may 50 be configured, for example
To determine the speed at the time when the switch 16 is turned off (for example, using signals from the speed detection part 32 )
either (a) adjust a waiting time (eg, according to the second embodiment described above) until the resistor brake (resistor) is connected to the motor M, or (b) determine when the speed of the output shaft falls below a prescribed threshold is (for example, according to the modified embodiment described above), and
then to connect the resistance brake (resistor) to the motor M to delay the motor M faster after the waiting time has elapsed, or the speed of the output shaft has been reduced to a predetermined speed.

In such dynamic dynamic braking embodiments, a single resistor (or a single resistor value obtained from a fixed set of resistors) may be connected to the motor M such that the resistance applied to the motor M is constant. According to an alternative, a set of resistors may be connected in parallel or in series, so that a variable braking resistor may be applied to the motor M, for example according to the previous modified embodiment, which uses variable braking.

1. 1. Eine elektrische Arbeitsmaschine mit:
   • einer Ausgangswelle, die derart konfiguriert ist, dass ein Werkzeugzubehör darauf durch Festschrauben einer Schraube montiert werden kann;
   • einem Motor, der die Ausgangswelle dreht;
   • einem Bedienteil zum Befehlen des Antreibens/Anhaltens des Motors; und
   • einer Steuerungseinheit, die das Antreiben/Anhalten des Motors gemäß den Befehlen von dem Bedienteil steuert;
   • wobei die Steuerungseinheit derart konfiguriert ist zum Erzeugen einer Bremskraft in dem Motor oder auf der Ausgangswelle, wenn der Motor angehalten werden soll, proportional zu einer Anziehkraft des Werkzeugzubehörs, die aufgrund der Drehzahlzunahme erzeugt wird, wenn der Motor gestartet wird, dass je größer die Anziehkraft ist, desto größer ist die Bremskraft.
2. 2. Elektrische Arbeitsmaschine gemäß Ausführungsbeispiel 1, bei der das Bedienteil ein Drehzahleinstellungsteil aufweist, das die Drehzahl einstellt, wenn der Motor angetrieben wird; und die Steuerungseinheit konfiguriert ist zum Steuern der Bremskraft, wenn der Motor angehalten wird, proportional zu einer eingestellten Drehzahl, die durch das Drehzahleinstellungsteil eingestellt worden ist, als der Motor gestartet wurde.
3. 3. Elektrische Arbeitsmaschine gemäß Ausführungsbeispiel 1, bei der das Bedienteil konfiguriert ist zum Einstellen der Drehzahl, wenn der Motor angetrieben wird, proportional zu einem Manipulationsausmaß des Bedienteils; und die Steuerungseinheit konfiguriert ist zum Steuern der Bremskraft, wenn der Motor angehalten wird, proportional zu dem Manipulationsausmaß des Bedienteils, wenn der Motor gestartet wird.
4. 4. Elektrische Arbeitsmaschine gemäß Ausführungsbeispiel 2 oder 3, bei der die Steuerungseinheit derart konfiguriert ist, dass wenn der Motor in dem Zustand angehalten wird, bei dem, nach einem Starten des Motors, die Drehzahl des Motors nicht die Drehzahl erreicht, die durch das Bedienteil eingestellt worden ist, die Bremskraft kleiner ist als die Bremskraft, die der eingestellten Drehzahl entspricht.
5. 5. Elektrische Arbeitsmaschine gemäß Ausführungsbeispiel 2 oder 3, bei der die Steuerungseinheit konfiguriert ist zum Einstellen der Bremskraft proportional zu der Drehzahl, wenn das Bremsen des Motors gestartet wird, wenn der Motor in dem Zustand angehalten wird, bei dem nach dem Starten des Motors die Drehzahl des Motors die durch das Bedienteil eingestellte Drehzahl nicht erreicht hat.
6. 6. Elektrisches Arbeitsmaschine nach einem der Ausführungsbeispiele 1 bis 5, bei der die Steuerungseinheit konfiguriert ist zum Steuern der Bremskraft, indem ein Bremsstrom, der zu dem Motor fließt, gesteuert wird, wenn der Motor angehalten wird.
7. 7. Elektrisches Arbeitsmaschine nach einem der Ausführungsbeispiel 1 bis 5, bei der die Steuerungseinheit konfiguriert ist zum Anhalten des Motors, wenn durch das Bedienteil ein Befehl eingegeben wird den Motor zu stoppen, indem der Fluss des Stroms zu dem Motor unterbrochen wird, und nach Verstreichen einer vorbestimmten Wartezeit ein Bremsstrom an den Motor angelegt wird, wodurch die Bremskraft durch Einstellen der Wartezeit gesteuert wird.

Instead of dynamic resistance braking, regenerative dynamic braking is also possible in electric rotary tools and machines powered by a rechargeable battery. In such embodiments, the power generated by the regenerative dynamic braking may be supplied to the rechargeable battery to be charged.

1. 1. An electric working machine with:
   • an output shaft configured such that a tool accessory can be mounted thereon by screwing a screw;
   • a motor that rotates the output shaft;
   • a control unit for commanding the driving / stopping of the engine; and
   • a control unit that controls the driving / stopping of the motor in accordance with the commands from the operating part;
   • wherein the control unit is configured to generate a braking force in the engine or on the output shaft when the engine is to be stopped in proportion to a tightening force of the tool accessory generated due to the speed increase when the engine is started, the larger the tightening force is, the greater the braking force.
2. 2. Electric machine according to the embodiment 1 in which the operating part has a speed setting part that adjusts the speed when the motor is driven; and the control unit is configured to control the braking force when the engine is stopped in proportion to a set rotational speed set by the rotational speed setting part when the engine is started.
3. 3. Electric machine according to the embodiment 1 in which the operating part is configured to adjust the rotational speed when the motor is driven in proportion to a manipulation amount of the operating part; and the control unit is configured to control the braking force when the engine is stopped, in proportion to the manipulation amount of the operating part when the engine is started.
4. 4. Electric machine according to the embodiment 2 or 3 wherein the control unit is configured such that when the engine is stopped in the state where, after starting the engine, the rotational speed of the engine does not reach the rotational speed set by the operating part, the braking force is smaller than the braking force that corresponds to the set speed.
5. 5. Electric machine according to the embodiment 2 or 3 wherein the control unit is configured to set the braking force in proportion to the rotational speed when the braking of the engine is started when the engine is stopped in the state in which, after starting the engine, the rotational speed of the engine is the rotational speed set by the operating part did not reach.
6. 6. Electric working machine according to one of the embodiments 1 to 5 in that the control unit is configured to control the braking force by controlling a braking current flowing to the motor when the engine is stopped.
7. 7. Electric working machine according to one of the embodiment 1 to 5 wherein the control unit is configured to stop the engine when a command is input by the operating part to stop the engine by interrupting the flow of the current to the engine, and applying a braking current to the motor after a predetermined waiting time elapses, whereby the braking force is controlled by adjusting the waiting time.

LIST OF REFERENCE NUMBERS

2

grinding machine

4

motor housing

6

gearbox

8th

rear housing

10

battery Pack

12

tool Accessories

14

wheel cover

16

slide switches

18

Speed change switch of the dial type

20

battery

22

spindle

24

inner flange

26

locknut

30

engine

32

Speed detection part

40

inverter

42

resistance

44

Detection part for an electric current

50

control

52

Acceleration setting part

54

Trigger manipulation portion

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2013243824 [0040]
• US 2013/307446 [0040]
• US 2013307446 [0118]
• US 9776338 [0122]

Claims (11)

Electric turning tool (2) with: an output shaft (22) configured to mount a tool accessory (12) thereon through a threaded connection (26); a motor (30) that directly or indirectly rotates the output shaft (22); a control part (16) for generating drive / stop commands for the engine (30); and a control unit (40, 50) that controls the driving / stopping of the motor (30) in part based on the drive / stop commands from the operating part (16); wherein the control unit (40, 50) is configured to cause a braking force to be generated in the engine (30) and / or applied to the output shaft (22) when the engine (30) is to be stopped, the control unit Brake force proportional to a magnitude of the torque applied to the threaded connection (26) as a result of acceleration of the output shaft during start-up of the engine (30) is variably set such that the larger the torque applied to the Output shaft (22) during the start of the engine (30), the greater the braking force that is generated or applied during the brake control, which is performed by the control unit (40, 50). Electric turning tool (2) after Claim 1 further comprising a speed setting part (18) configured to variably set a target speed when the motor (30) is driven to perform a machining operation; wherein the control unit (40, 50) is configured to control the braking force while the engine (30) is stopped, in proportion to the target speed set by a user using the speed setting part. Electric turning tool (20) with: an output shaft (22) configured such that a tool accessory (12) is mountable thereon by a threaded connection (26); a motor (30) that directly or indirectly rotates the output shaft (22). a control part (16) for generating drive / stop commands for the engine (30); a control unit (40, 50) that controls the driving / stopping of the motor (30) in part based on the drive / stop commands from the operating part (16); and a speed setting part (18) configured to variably set a target speed when the motor (30) is driven to perform a machining operation; wherein the control unit (40; 50) is configured to cause a braking force to be generated in the engine (30) and / or to apply to the output shaft (22) when the engine (30) is to be stopped; Control unit (40, 50) variably adjusts the braking force in proportion to the target speed, which has been set by a user using the speed setting part (18). Electric turning tool (2) after Claim 2 or 3 wherein the speed setting part (18) is configured to variably set the target speed when the motor (30) is driven in proportion to a manipulation amount of the speed setting part (18). Electric turning tool (2) after Claim 2 . 3 or 4 in that the control unit (40, 50) is configured so that when the engine (30) is stopped in the state in which, after starting the engine, the rotational speed of the engine (30) has not reached the target rotational speed, was set using the speed setting part (18), the braking force is set smaller than a braking force corresponding to the target rotational speed. Electric turning tool (2) after Claim 2 . 3 or 4 wherein the control unit (40, 50) is configured to set the braking force in proportion to an actual rotational speed when the engine (30) is to be stopped in the state where, after starting the engine (30), the rotational speed of the engine (30) has not reached the target speed set using the speed setting part (18). Electric turning tool (2) according to one of Claims 1 to 6 wherein the control unit (40, 50) is configured to control the braking force by controlling a braking current flowing to the motor (30) while the motor (30) is stopped. Electric turning tool (2) according to one of Claims 1 to 6 in that the control unit (40, 50) is configured to stop the motor (30) when the stop command is input by the keypad (16) by first stopping the flow of the current to the motor (30) without applying one Braking force to the motor (30) or to the output shaft (22) for a predetermined waiting time, and then, after the lapse of the predetermined waiting time, a braking current is applied to the motor. The rotary electric tool (2) according to any one of the preceding claims, wherein the control unit (40, 50) is configured to select the braking force in proportion to an angular pulse applied to the output shaft (22) during a time interval between standstill of the engine and a time at which the engine reaches its maximum peak speed during engine starting (30). Electric rotary tool (2) according to one of the preceding claims, in which the acceleration of the output shaft (22) during the starting of the engine (30) is at least substantially constant or follows a predetermined acceleration profile, and the control unit (40, 50) is configured to set the braking force in proportion to a peak speed of the engine (30) during a machining operation. An electric turning tool (2) according to any one of the preceding claims, wherein the rotary electric tool is a grinding machine, a circular saw or a lawn mower.

Images